johnson



J 1953; H. A. JOHNSON 2,642,047

METHOD OF ADJUSTING INJECTORS 2 Sheets-Sheet 1 Filed Dec.- 2, 1948 3nventor ohnson m v J June 16; 1953 JOHNSON 2,642,047

METHOD OF ADJUSTING INJECTORS Filed Dec. 2, 1948 ZSheets-Sheet 2 [HI llll g L ig l/1421111 5? 21 Sii 3a 3nventor Harry Amos Johnson Gttornegs Patented June 1,6, 195 3 UNITED "STAT S ATENT F CE I .1 Q i 5, 2,642,047 j, a I a METHOD oF-A JUs'riNG'I JEoroRs Harry Arnos'Johnson, Omaha, Nebr. l Application December 2, 1948. Serial No. 53,039

' This invention relates. to a method of, adjusting the injectors of a multi-cylinder compression-ignition engine, and to a gage for use in practising said method.

Simply as a convenient Way ofdisclosing the principle of the invention, it will be described as '1 Claim. (01. 123-1) usedwith aseries 71 General Motors diesel en- 7 gine, which is atypical commercial engine. 'It is applicable to any engine in which .single master controller actuates a plurality of control racks through individually adjustable connections.

-The master controller in this engine is popularlycalled the control tube. Mechanically it is a shaft rotatable by an actuating arm through a small angle. It is constructed as a tube to secure good torsional rigidity with respect to weight. Encircling the control tube, and angularly adjustable with referencethereto by means of pairs of opposed tangent screws are control connectors one for each engine cylinder and each connected to the control rack for the injector of that-cylinder- The term control rack is commonly applied to thefuel adjusting element of any fuel injector. In most, but not all, fuel injectors it is literally a toothed rack that em I each control rack has the same initial critical position, and thesame range of motion as were Y established by adjusting the first control connector. v The best practice is to start by adjusting the control connector nearest to the actuating arm. The reason that this is done is to minimize the error occasioned by possible torsional fiexure of that a much more uniform standard of performgages. and turns a pinion on some part, commonly the plunger, of the fuel injector pump, to vary the measured displacement of "that pump.

Such pumps are familiar to persons skilled in the diesel engine art and require no detailed description. The problem of adjustment has to do with the positional relation of each control rack relative to the actuator. This is true regardless of the details'of'construction of the engine. To adjust the specified General Motors engine, the

- control connectors must be angularly adjusted 'on' the control tube by setting the tangent screws, and a correct setting is one in which all the cylinders receive equal charges of fuel in each of the various positions of the control tube.

The adjustments are made, according to the invention, by freeing all the control connectors. One of said control connectors is adjusted ,by proper manipulation of the tangent screws. A

ance can be maintained.

A preferred embodiment of my invention is shown inthe accompanying drawings in which:

Fig. 1 is a fragmentary perspective view of an engine with thegage in place.

Fig. 2 is a fragmentary front'elevationof the engine in which obstructing parts have been broken away showing the gage in place.

Fig. 3 is a detail view, partly in section of an injector control connector and the control tube.

Fig. 4 is a top view of the gage.

Fig. 5 is a side View of the gage partly in section. I I

Fig. 6 is a section of the gage'taken on the line 6-6 of Fig. 5.

Fig. 7 is a section of the gage taken on the line l'---'! of Fig. 5.

Fig. 8 is a detail sectionof the movable anvil of thegage."

' Fig. 9 is a perspective view showing the movable anvil of the gage.

The engincs cylinder head and injectors are shown at 2.

isindicated at a, A bearing bracket 3 is mounted on the head i, and in it the conspecial direct reading micrometergage is applied to the actuating arm. The gage readings for certain critical positions of the actuating arm are noted. With the gage still in place, the other injectors are successively adjusted so the same critical readings are maintained. I r

Theadjustment of thefirst-control connector limits the range of motion of the control tube. By careful observation of the gagegthe remaining control connectors may be adjusted, sothat trol tube 4 is journaled. There is a similar bear ing bracket, not shown, mounted. at the other end of the head I and supporting the other end of the control tube 5. Mounted on the tube are a plurality of control rack connectors 5. The outer ends of the connectors Eifare linked to respective control racks B. The control rack connectors 5 are angularly adjustable about the tube 4 and may be moved by loosening the tangent adjusting screw 3 and tightening the tangent adjusting screw" '3' and vice-versa. Adjusting screws 1 and B engage re'spectivenotches 9 and I9 formed in the control tube (see Fig. 3). 'A V 3 rod I2 leads from the governor l3 to the control tube actuating arm 14. The rod I2 is hinged to the arm l4 by means of a pin l5.

A specially designed gage I6 is mounted between the head I and the pin [5 as shown in Fig. 1. The gage I6 comprises a cylindrical body IT. A bracket I8 is fastened to the body I! by machine screws I9. The bracket I8 is formed with the prongs 2i and 22. Prongs 2i engage the upper horizontal face of the cylinder head and prongiZZ "engages the inner nearly vertical face. The body I! has an axial bore 23 in which is properly set.

is slidable the rod 24 which has an enlarged por-' tion 25 which has the same diameter-as the ,bore

23. A cap 26 with opening 27 encircles the rod Hand is fastened to the end of the body l-l by screws 28. A spring 28 biases the rod outwardly of the bore 23. An anvil 29 of channel form is mounted on the outer end of rod 24. The

notches I'll provide means for engaging the pin l5-whenrthe gage .is-in place. -.on the engine. The member 2931s cut awayatii-lil.topermit free passage'of rod 1-2. A bracket-3 2 is .fastenedtothe body by screws 33. Guided on the bracket .32 is :a slide -34-which carries ;a conventional .indicating gage 35 as shown. in l ligfl'l.

The indicating gageafi is :preferably of the multiplying direct--reading.micrometer type. The feeler 36 is connected through a vmotion multiplying. train to the pointer 31. The pointer ii'l is arranged-so that, its axis-of rotation-coincides with the axis aboutwhich the dial. 40-may be manually set. This last is a :familiarzeroing adjustment. Fastened to the slide is a spacer 38. A set screw-39..is carriedby the spacer. 38 and engages. a recess-4 l in. the bracket .32.

The control .racksare adjusted-inthe-following manner. Numberfone injector, i. e. the one near-- est the actuating arm I4 is ordinarily the firstone which is .to be :adjusted. Preparatory to such adjustment, adjusting screws ofall the-control rack connectors are aloosened and the governor control (not shown), is set inthe .idleposition. Tangent, adjustingscrew -l is tightened thus moving the 'controle-rackcfi to the rig-ht as seen-in Fig. 2 toward its full fuel position; When the control-rack 6 reaches .fullj'fuel .position, its motion is arrestedand the icontroltube 4 starts to rotate. Rotation of'jthe controltube 4 is-resisted tby the governor rsprin'gs which Preact on the rod l2. When the resistance to the tightening :of this. screw noticeably-increases, indicating that the control rack 6 has been arrested-byits having reached :full; fuel position the: governor control is moved toward full fuel zposition and the adjustingscrew l is loosened#suflicie'ntiy{to permit the governor control to reach :full- 'fuel position. The adjusting screw "8- 'is th'en tightened. The gage i5 is then mounted so thatthe prongs 2| rest on the horizontal face of the lip of the cylinder head and the prong 22 engages the vertical face of the lip and the movable anvil receives the pin l5 in the notches 3|.

The set screw 39 is then loosened and the slide 34 carrying the indicating gage is moved along the bracket 32 until the feelertfi contacts the movable anvil 29 and the pointer has made one complete revolution. This assures the removal of any slack from the gage. The set screw 39 is then tightened. The dial 40 is then rotated untilthe zero marking coincides with thepointer indication. When the governor control is then moved from full f uel position back to idIcVpOsition the gage should :registena deflection ;of,.ap-

The manner of adjustment of number one injector prior to application of the gage as above described follows the usual present practice. Any errors indicated by the gage may be corrected by making such adjustments as are necessary not only to the control connector but also to the governor. Since these adjustments are not: a part of this invention. they will not be elaborated upon.

After number one injector has been properly adjusted, the mechanic may proceed to adjust number two injector. The adjustment of the number one injector establishes a definite range through .which the master control element may move asthe governor control is moved from idle to full fuel position. The remaining connectors couldibeset in positions which would not affect this range, but whichfpositions would be improper. The, governor control isset .inidle position. Tangent-adjusting.screw 1' is tightened moving .connector 5. and its associated control rack 6 toward full fuel .position. When the control .rack- 6. reaches its full fuel position, it can travel .no further. .Further tightening of the, tangent adjusting, screw 1 will result. .in-the displacement of the control tube 4 which would change .the gage reading. .Over-tightening-of screw .1 will cut down the range of motion through which .the controltube can -moveand destroy the adjustment of the injector 2, i. e...the number one .injector. .In-practice, therefore, screw 1' is tightened untilthe.hand on the gage indicates. thatthe control tube .-.is starting. to move. At .thistime tangent. adjusting .screw 8 is tightened. Itv makesnodifferences in what position the governor-.control is when this ad.- justment is madeto number two.injector,..but it is ordinarily performed with the. governor controlin .idleposition. However, it isimperative that. theflpointer 3'Lstart to move slightly as thislassures that. the control rack- 5 rhas-the same initial, position .asthe controlrack 6. As thegovernor contr-olis 'againmoved from idle to full f-uel-pos'itionthe samedefiection of approximately 0.003 inch should result. If the .defiection is lessthan that amount, the tangent adjustingscrew l is too tight- 'Both tangent-adjusting-screws 1'.and,8'..shou1d be loosened, and 'i' tigh-tened again, being sure thatthepointer S'Lmoves only veryslightly.

When .numbertwo injector is properly ad? justed the procedure is repeated .onnumber three injector .andso on for each successive. injector in the engine.

It willbe understood thatwhile the gage readings for the idle and full fuel positions of the governor...contro1 arethe critical readings for. the purposes of the described embodiment, other critical-readings and positionswill suggest themselves to thoseskilled in the art when using't-he method in. connection with othermakes of engine.

.I claim:

The method, of coordinating the movement. of the control racks of the fuel injectors of a multi-cylinder-compression ignition engine of the type .in whichaa single -.master control element actuates-the racks, one for each injector, through an adjustable linkage whereby said rack and said control element maybe, moved relatively ,to each other whichmethod comprises commencing with oneof said control racks properly adjusted relatively .to said element, motion. of said control- 1 element :and said 1 adjustedrackbeing thus limited at one of its extremes by arrest of said rack, and limited at its other extreme by arrest of said control element; mounting a direct reading gage between said element and a fixed part of the engine; setting said control element and the adjusted rack at one of said limits;

adjusting the linkage associated with a second 7 injector so as to move its associated control rack relatively to said element and toward its limiting position; discontinuing such movement of the rack when it is arrested, arrest of said rack being indicated by movement of the control element and the associated gage; setting the linkage being adjusted and the associated control rack at the point where its arrest occurs; and with the gage still in place setting any remaining unadjusted control racks in the same manner as said second control rack.

HARRY AMOS JOHNSON.

References Cited in the file or this patent UNITED STATES PATENTS Number Name Date 1,587,743 Baker June 8, 1926 2,043,162 Foster June 2, 1936 2,069,043 Miller Jan. 26, 1937 2,437,283 Viers Mar. 9, 1948 2,443,135 Glotfelty June 8. 1948 OTHER REFERENCES Maintenance Manual for Series '71, Two Cycle Diesel Engines, Oct. 1948, Detroit Diesel Engine 1 Division, General Motors Corp; Detroit, Mich. 

